A. Field of the Invention
This invention relates to the field of flexible web handling and processing; especially the handling of webs supplied on long rolls known as bobbins. More specifically, this invention relates to a method and apparatus for inserting a tab into a web of paper in high-speed manufacturing procedures which involve a converting step, e.g. laser perforation, menthol application, or the like.
B. Description of the Related Art
It is customary in the art, e.g. of cigarette manufacturing, to perform converting functions on lengthy rolls of paper or the like provided in bobbins. Bobbins are long lengths of the flexible material wound up upon a core. Cigarettes use substantial amounts of paper in their production--as a packaging material, a cigarette wrapper, to enclose filter tow material as filters, and to tip filters onto columns of wrapped tobacco, to name a few exemplary uses. As used herein, "web" refers to not only paper, but also includes foils, fabrics, polymer tapes, etc., which are supplied in a lengthy form suitable for storage in bobbins.
Conversion as used herein refers to a function such as application of a substance (e.g. menthol, adhesive, odorants); perforation, either mechanically or by thermal energy transfer (e.g. focused laser energy or the like), printing, embossing, slitting, or other comparable functions on paper, films, or other flexible webs.
For ease of illustration; however, a single embodiment will generally be referred to in the specification (application of menthol to a metal foil), but one of skill in the art may easily see where this disclosure may have a wide range of applications. The protection afforded by this application should therefore be measured with reference to the appended claims and not the examples herein.
During converting, some amounts of paper, foil, or the like (usually at the beginning of the web) are lost as waste because of insufficient, incomplete, or no processing. The processing starts at a certain point along the web to be of acceptable quality.
It would be desirable to provide a device which could identify and help segregate the waste material such as this.
Presently operational machines address this segregation requirement in a rather primitive fashion. An operator manually places an adhesive tab on a swinging arm having a flat surface adapted to receive the adhesive. The arm is arcuately movably positioned between the web path and a roller downstream from the converting apparatus. Upon extension of the arm, the tab is inserted into the space between the web and the roller, where it is "pinched" sufficiently to adhere to the paper and be pulled off the arm. The tab is then wound up into the spool of converted web material and signifies the end of the good material.
Placement of the adhesive tab is critical, as the swinging arm is brought into a very close contact with the paper. If too much of the tab adheres to the arm it will not be inserted, or will tear, or become misaligned and cause a web jam in the machine, or a break in the web.
It would be useful to have a more reliable method of inserting a tab into the wound up web on a spool which would be less dependent on operator skills and provide a precise placement on the web, thereby further reducing waste.
Other art known to the applicants is as follows. Each of the following cited patents are hereby incorporated in their entireties by reference.
U.S. Pat. No. 4,715,390 discloses the coating of plug wrap with a menthol by way of example, and U.S. Pat. No. 5,249,416 describes the use of a packaging stock with a pre-applied adhesive. U.S. Pat. No. 4,846,454 describes an apparatus for manufacturing forms from a continuous web of paper by cutting the web on electronic command from a sensor which detects a preprinted separation mark. Finally, U.S. Pat. No. 3,625,226 describes a marking device for marking a wrapper containing cigarettes. Once a preselected number has been counted, an electromagnet is energized to mark the wrapper tape in the machine.
In conventional operation, rolls of material are generally unwound, the conversion function is performed upon the paper, and the new bobbin wound up on a new bobbin core.
However, it is inevitable that losses are incurred during the conversion at conversion startup. For example, the web speed is constantly changing as it ramps up to operating speed and it has been heretofore virtually impossible to control the amount of ink, pressure, adhesive, embossing, etc. being applied. Conventional rewinders in the laser perforating area can cause the loss of about 25 meters of paper at startup.
As noted above, this wasted paper is generally wound about the core of the rewinder, and an adhesive tab inserted into the bobbin at the point where the menthol application, perforation or other conversion is within acceptable limits or of sufficient quality to be inserted into consumer or other goods, usually at a thickness of about 8 mm around the core; often as much as 12-14 mm. Segregation of this waste is thus important to prevent further downstream manufacture of finished products and additional wastage.
The only known equipment is discussed above, and its reliability is subject to improvement, given the waste which can occur if a tab is incorrectly inserted, not inserted at all, or causes a paper jam. A solution to this problem is needed.